Compairing html string to hex string with php - php

Question

I am trying to compare two strings. When compared they are unequal to the computer. But to the human eye the strings appear to be the same.
When I run a test to check the bin2hex with php they are clearly unequal. Some how a set of double quotes is be read as html. Here are some examples:
$string1 = strlen(html_entity_decode($_SESSION['pageTitleArray'][$b]));
$string2 = strlen(html_entity_decode($value));
echo 'Checking: ' . $_SESSION['pageTitleArray'][$b] . " " . bin2hex($_SESSION['pageTitleArray'][$b]);
echo '<br>';
echo 'testing ' . $string1 . " = "bin2hex($string1) . " " . bin2hex($string2);
echo '<br>';
echo 'With: ' . $value . " " . bin2hex($value);
The code above will out put the following information.
Checking: 1 PAIR OF BBC HEAD GASKET GASKETS MULTI LAYERED STEEL 4.585"
312050414952204f46204242432048454144204741534b4554204741534b455453204d554c5449204c41594552454420535445454c20342e35383522
testing 3630 3632 With: 1 PAIR OF BBC HEAD GASKET GASKETS MULTI
LAYERED STEEL 4.585″
312050414952204f46204242432048454144204741534b4554204741534b455453204d554c5449204c41594552454420535445454c20342e3538352623383234333b
false
I am kinda lost on what to do... Any help would be greatly appreciated. Below is the rest of the code so you can get a total feel for what I'm trying to accomplish.
for($b = 0; $b < count($_SESSION['pageTitleArray']); $b++)
{
foreach($_SESSION['pushIdArrayQuery'] as $key => $value)
{
$string1 = strlen(html_entity_decode($_SESSION['pageTitleArray'][$b]));
$string2 = strlen(html_entity_decode($value));
echo 'Checking: ' . $_SESSION['pageTitleArray'][$b] . " " . bin2hex($_SESSION['pageTitleArray'][$b]);
echo '<br>';
echo 'testing ' . $string1 . " = "bin2hex($string1) . " " . bin2hex($string2);
echo '<br>';
echo 'With: ' . $value . " " . bin2hex($value);
if(trim($_SESSION['pageTitleArray'][$b]) == trim($value))
{
echo '<br>';
echo '<h1>Success</h1>';
echo '<br>';
echo '<b>Key: </b>' . $key;
echo '<br>';
echo 'Page Id: ' . $_SESSION['pushTitleArrayQuery'][$key];
echo '<br> ';
}
else {
echo '<br>';
echo 'false';
echo '<br>';
}
}
}

Answer 1

You have two different types of quotations mark (" on the first string and ″ on the second one).
To human eyes they seems similar but they are complete different characters to PHP.

Answer 2

This is how I fixed the problem. Notice, I removed any html attributes with the html_entity_decode() function. Then, from there I was able to strip away all other special characters by using preg_replace() and compare the results.
//Loop through all the page titles from the directories
for($b = 0; $b < count($_SESSION['pageTitleArray']); $b++)
{
//Loop through the page titles gathered from the database
foreach($_SESSION['pushTitleArrayQuery'] as $key => $value)
{
//use html decode to remove the quotes with ENT_NOQUOTES
$removeHtml = html_entity_decode($value, ENT_NOQUOTES);
//Test to make sure the encoding are the same for both variables.
$detectEncoding = mb_detect_encoding($value, "auto");
//remove all non alphanumeric variables in the first string.
$string1 = preg_replace("/[^a-zA-Z0-9]/", "", $_SESSION['pageTitleArray'][$b]);
//remove all non alphanumeric variables in the second string.
$string2 = preg_replace("/[^a-zA-Z0-9]/", "", $removeHtml);
//Print out to see what the results look like from decode and encoding functions
echo 'Testing the removal of html quotes: ' . $removeHtml . ' Encoding: ' . $detectEncoding;
echo '<br>';
//Show what variables are being compaired.
echo 'Checking: ' . $string1 . " " . bin2hex($_SESSION['pageTitleArray'][$b]);
echo '<br>';
echo 'With: ' . $string2 . " " . bin2hex($value);
//If statement to check if the to strings match.
if(trim($string1) === trim($string2))
{
echo '<br>';
echo '<h1>Success</h1>';
echo '<br>';
echo '<b>Key: </b>' . $key;
echo '<br>';
echo 'Page Title: ' . $_SESSION['pushTitleArrayQuery'][$key];
echo '<br>';
echo 'Page Id: ' . $_SESSION['pushIdArrayQuery'][$key];
echo '<br> ';
}
else {
echo '<br>';
echo 'false';
echo '<br>';
}
echo '<br>';
}
}